37 
a. Unionina. Foot moderate. 
1. UNIo. 
1. U. pictorum, t. 359. f. 2, t. 363. f. 2, t. 364. f. 3, 4 (fig. 20). 
Fig. 20.— Unio pictorum. 
Right valve and mantle lobe removed. aa’, adductor muscles. pp’, pedal 
muscle and accessory pedal muscle. u,umbo. 7, ligament. 4, bran- 
chial orifice. v, anal opening. f, foot. o, mouth. #, palpi or lips. 
bo 
. U. patagonica, t. 364. f. 5. 
. U. Feldmanni, t. 360. f. 3. 
. U. guaraquana, t. 364. f. 1. 
U. Solisiani, t. 364. f. 2 
os 
Ww 
Cre ¢ 
2. ANODON. 
A: anatinus, t. 360. f.1, 2, t. 362. £.1, 2, 3, t. 363. f..1 (fig. 21). 
A. latomarginata, t. 361. f. 1. 
lee 
Fig. 21.—Anodon anatinus (female). 
=e Se hc 
J, the foot, contracted. a, anterior adductor muscle. p, palpi. g, inner 
gills. 0, outer gills distended with spawn. 4, a bristle passed through 
one of the dorsal channels. 
3. LIMNOICcA. 
1. L. linearis, t. 363. f. 3. 
4. Damanis, 
1. D. margaritifera, t. 328. f. 3. 
